Apple Inc. shares hit a record after Warren Buffett told CNBC he bought an additional 75 million shares of the iPhone maker in the first quarter.

The Apple purchase, costing between $11 billion and $14 billion, adds to the almost 170 million shares that Buffett-run Berkshire Hathaway Inc. owned at the end of 2017, when it was already his biggest shareholding.

Just days before Buffett disclosed the larger stake, Apple reported quarterly results that topped analysts’ estimates on surging services revenue and stable iPhone performance. The numbers helped end a recent swoon in Apple stock on concern its flagship iPhone X model wasn’t selling as well as Wall Street originally hoped.

“It is an unbelievable company,” Buffett said in the CNBC interview. Berkshire Hathaway is holding its annual meeting this weekend in Omaha, Nebraska. Buffett said the company’s exact holdings will be disclosed in a quarterly regulatory filing Saturday.